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Greenhouse effect

Objectives

After this lesson, students should be able to:• Define the term greenhouse effect.• Explain the mechanisms of greenhouse effect.• Explain what are the effects of global warming

on Earth and its inhabitant.• State and discuss the problems that would be

brought up by global warming.• Discuss the solutions to prevent global warming.

INTRODUCTION

Introduction to Greenhouse effect

• What happens to a car that has been sitting in the sun on a hot day with all its windows rolled up?

WHAT IS “GREENHOUSE EFFECT”?

What is “Greenhouse effect”?

• The Greenhouse effect is caused by an atmosphere containing gases that absorb and emit infrared radiation.

– Greenhouse gases trap heat within the surface-troposphere system, causing heating at the surface of the Earth.

MECHANISMS OF GREENHOUSE EFFECT

Mechanisms of Greenhouse effectSunlight brings energy into the climate system; most of it is absorbed by the oceans and land.

Heat (infrared energy) radiates outward from the warmed surface of the Earth.

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Some of the infrared energy is absorbed by greenhouse gases in the atmosphere, which re-emit the energy in all directions.

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THE GREENHOUSE EFFECT:

Mechanisms of Greenhouse effect

Some of the infrared energy further warms the Earth.

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Some of the infrared energy is emitted into space.

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GLOBAL WARMING

Mechanisms of Amplified Greenhouse effect

Higher concentrations of CO2 and other "greenhouse" gases trap more infrared energy in the atmosphere than occurs naturally. The additional heat further warms the atmosphere and Earth’s surface.

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AMPLIFIED GREENHOUSE EFFECT:

Sunlight brings energy into the climate system; most of it is absorbed by the oceans and land.

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Greenhouse gases

• Major greenhouse gases are:– Water vapour– Carbon dioxide– Methane – Nitrous oxide– Ozone– Chloroflurocarbon (CFC)

Causes of Global Warming

• These are the major causes of global warming:–Volcanic eruption– Solar and orbital variations.–Human activities (due to the increasing human

population)• Burning of fossil fuel.• Clearing of rainforest.

Problems caused by global warming

• Increase in global temperature.• Melting of ice in Polar Regions.• Rising of sea level.• Increase in extreme weather events.• Mass extinction of flora and fauna species.

Solutions to prevent global warming

• Use of Renewable energy.– Wind– Hydroelectric– Waves– Solar– Thermal

• Use of Nuclear to generate energy.• Reforestation.• Conservation of energy.

SUMMARY

• Definition of “Greenhouse effect”. • Simple description of the mechanisms. • Increase in Greenhouse gases results in Global

Warming. • Solutions to halt the increase in greenhouse

gases.